Scooters may include man-driven and power-driven scooters. Most of the man-driven scooters and power-driven balance vehicles require drivers to have good driving skills to keep a balance in all directions such as front, behind, left or right. However, since the power-driven scooters usually adopt a self-balancing system including a gyroscope, an acceleration sensor and the like for keeping a balance of a vehicle body, the power-driven scooters do not have so high requirement for the driving skills of drivers as the man-driven scooters.
At present, the scooters on the market include two-wheeled scooters and monocycles. Since a single-wheeled balance vehicle has only one wheel and includes operations for keeping a balance of a body, it has a relatively high requirement. The key distinction between the man-driven monocycle and the power-driven monocycle includes that the sources of power are different and the latter is equipped with a self-balancing system, as well as including other differences derived therefrom. Therefore, the power-driven single-wheeled balance vehicle is mainly introduced in the related art as follows.
The Chinese patent application No. CN 99103781 titled as “one-wheel motor and spherical vehicle” proposes a spherical monocycle. Since the whole weight of the monocycle is almost supported by the only one wheel when the monocycle is driving on the road. The entire monocycle drives by the only one wheel on the ground. When the monocycle turns, a pair of torsional moments at a certain level directly (through a simple mechanism) provided to a whole vehicle body by rotating a steering wheel (or the direction joystick) by a driver (it takes naturally a landing point of one wheel as a rotation center) to twist the entire monocycle rotate one driving direction. Thus, during a driving process, the monocycle cannot automatically maintain a front-rear balance so that it has a high requirement for the driving skills of drivers.
The Chinese Taiwanese patent application No. TWM403480 titled as “electric monocycle” proposes an electric monocycle with footboards and auxiliary wheels. A drive-by-wire operated handle is used to control forward and backward, and a balance of left or right side is kept by the auxiliary wheels. Drivers must grip a vehicle body and twist both legs or both feet reversely so as to turn when the electric monocycle is turning and in a driving maneuvering action. Due to existence of the auxiliary wheels, both legs or both feet should be twisted with a greater force to drive to swerve, and the leg will exert a larger force on a side plate in swerves.
The U.S. Pat. No. 8,459,667 B2 titled as “foot propelled hobby and/or sport device without handle bar” proposes a monocycle including a rear-side stabilizing guide wheel, a side plate, a supporting surface for a knee or leg so that a driver can drive when standing. Since the side plate and the supporting surface for a knee or leg are provided, each leg of the driver and the monocycle form a 2-point connection in a vertical direction, so that a left-right balance of the monocycle can be controlled in the form of walking on stilts easily and a driving difficulty of a standing monocycle is reduced.
The Chinese patent application No. CN 02807642 titled as “vehicle and method of using gravity and mass transfer control system”, the U.S. Pat. No. 6,302,230 titled as “personal mobility vehicles and methods”, and the U.S. patent application No. 2009/0266629 titled as “motorized transport vehicle for a pedestrian”, propose a method and device for driving an actuator by a specific algorithm by detecting a change in a center of gravity of a person/vehicle system to achieve a dynamic balance so that a dynamically front-rear balancing vehicle becomes possible.
The Chinese patent application No. CN 200810179658 titled as “front-rear self-balanced electric monocycle” proposes an electric monocycle including seats, handrails, and an electronic control system, which can control the monocycle to keep a front-rear balance automatically. The electric monocycle is driven when a driver sits down, uses a manner of a traditional single-wheeled bike for keeping the left-right balance, and provides an automatic balance function in front and rear directions so that it is easy to drive.
The Chinese patent application No. CN 201110089122 titled as “electric single-wheeled bicycle” proposes an electric one-wheeled bicycle including a leg contact plate and foldable footboards, which has a self-balancing function in front and rear directions. As in the U.S. Pat. No. 8,459,667 B2, it proposes to use a leg contact device and the footboards to form two-point support to a driver so that the driver can stand and drive with legs and feet to control a bicycle to keep a balance at left and right side and turn.
In summary, a wheel cover (vehicle housing) of the abovementioned monocycle also has a left and right two-piece structure. A distance between the wheel cover and the tire/hub is limited. Under the lateral force applied by legs, or when a road surface is uneven, the wheel cover deforms and fails very easily, rubbing or blocking tires. Especially for the monocycle having the front and rear self-balancing function, a speed of a motor is directly related to a front-rear pitch gesture of a monocycle body. Once the tire is rubbed or blocked by the wheel cover, it is easy to cause the motor to have a high speed or be blocked, so that the driver loses his balance and falls, which has a security problem; once the wheel cover is worn or damaged, because of its large size, complex structure and high cost, it is inconvenient in replacement and high in maintenance costs.
For two-wheeled vehicles, due to uneven road or other possible reasons, it is easy to lead to problems similar to the abovementioned monocycle, which will not be described in detail.